Summary of the invention
The object of the invention is to provide a kind of can ensure that the online clamp force adjusting device of the actual clamp force in press casting procedure in range of set value and clamp force regulate algorithm to solve above-mentioned the deficiencies in the prior art.
To achieve these goals, the die-casting machine die-locking power on-line control device designed by the present invention, comprises three parts such as clamp force on-line detecting system, feedback control system and mode transfer executing agency.
Described clamp force on-line detecting system is made up of strain-type force sensor, modulate circuit; Strain-type force sensor is by strain gauge adhesion on elastic component, is connected in tightly on the pull bar of die casting machine with steel band, obtains the deflection identical with pull bar.Can install on a pull bar on strain-type force sensor or four pull bars and respectively strain-type force sensor is installed.It is then more accurate that four pull bars are installed, be exactly total it is made a concerted effort clamp force.Every root pull bar can adopt by one group, two groups or four groups of strain-type force sensors, conventional two groups of strain-type force sensors, are separated by 10 ° and arrange, to eliminate the Lateral Force generation Bending Influence because reason in structure causes, improve measuring accuracy; Often organize strain-type force sensor to be made up of the two panels foil gauge of a vertical and one horizontal, can temperature-compensating be realized, eliminate the impact of environment temperature, improve measuring accuracy further.The modulate circuit of clamp force on-line detecting system is a kind of bridge circuit in essence, the resistance change of foil gauge is converted to voltage and through suitably amplifying to export through suitable voltage.One group of strain transducer is connected into half-bridge, and two groups of strain-type force sensors are connected into full-bridge, is connected into full-bridge after four groups of strain-type force sensors then can adopt series connection, and then improves the sensitivity of test.Strain-type force sensing is delivered to feedback control system by signal cable after being connected into electric bridge.Strain-type force sensor is arranged between the template of front and back, and distance pull bar is greater than pull bar diameter at the end that is fixedly connected of front and back template and does not affect the position of clamping motion, to obtain uniform Strain Distribution.
Described mode transfer executing agency comprises hydraulic motor, driven wheel, adjustment pinion, adjustment nut and mode transfer gear wheel.Hydraulic motor front end can be passed through reducing gear or directly drives mode transfer pinion rotation, pinion to drive adjustment nut again by driven wheel drive mode transfer bull gear drive, mode transfer gear wheel, changes the distance between two templates on pull bar.Hydraulic motor, mode transfer gear wheel etc. are bearing on rear pattern plate, move with rear pattern plate; Mode transfer pinion to be bearing on adjustment nut and to transmit power by key connecting, converts the rotation of mode transfer pinion-adjustment nut the movement of adjustment nut on pull bar to.Adjustment nut is arranged on the rear of rear pattern plate, the mobile relative position changing forward and backward mould of adjustment nut, when locking mechanism in casting machine and die size constant change matched moulds time deflection, thus change the size of clamp force.
Described feedback control system is made up of encoder, controller and control performing a programme unit.Encoder and hydraulic motor are coaxially installed, and detect the angle that hydraulic motor turns over, and provide the corresponding rotational angle of stable mode-locking power required adjustment deflection.Controller is used for the difference of comparative analysis actual measurement clamp force peak value and setting value, according to the result of the controlling extent that controlling calculation provides, implements to carry out clamp force adjustment; Control performing a programme unit be strained by clamp force and bar stress, performing a programme that clamp force difference that mode transfer executing agency drive connection and comparator provide works out the start and stop of hydraulic control motor.
Present invention also offers a kind of control algolithm of die-casting machine die-locking power on-line control device, it specifically comprises the following steps:
Relation between the tensile force f that the pull bar a) setting up locking mechanism in casting machine is subject to and the strain stress that pull bar produces, the diameter d of above-mentioned relation and pull bar self or cross-sectional area A (A=π d
2/ 4), the elastic modulus E of material therefor is relevant:
Its physical relationship formula is: ε=F/EA=4F/E π d
2or F=ε EA=E π d
2ε/4;
By Hooke's law, for the pull bar by axial tension effect, its axial normal strain is ε, and transverse strain is-v ε, and wherein v is Poisson's ratio;
B) Strain Method is adopted to measure the actual pulling force of every root pull bar, pull bar is fixed one group or two groups of strain-type force sensors, the above-mentioned strain-type force sensor mentioned is made up of two foil gauges, a slice is along the longitudinal direction impression axial strain identical with pull bar of pull bar axis, and another sheet is experienced transverse strain and is combined into electric bridge and measures;
Adopt one group of strain-type force sensor to connect into the strain of measuring bridge measurement pull bar, measuring circuit forms half-bridge, its strain stress and bridge output voltage u
0pass be:
In formula: u
efor supplying bridge voltage; S is foil gauge sensitivity; V is the Poisson's ratio of measured piece;
Two groups of strain-type force sensors are adopted to connect into the measuring bridge form of full-bridge, its strain stress and bridge output voltage u
0pass be:
For concrete measuring object and test circuit u
e, s, (1+v) be definite value, if
be called electric bridge coefficient, then adopt one group of sensor, half bridging method coefficient is k, adopt two groups of sensors, full-bridge connection, coefficient is 2k;
According to the output voltage of measuring circuit and measurement, suffered by the pull bar that can obtain measuring gained, pulling force is:
One group of strain-type force sensor (half bridge measurement):
Two groups of strain-type force sensors (full bridge measurement):
C) the die casting machine tensile force f that upper connecting rod bears by calculating in previous step determines clamp force P, when measuring using the measurement of four draw-bar pulls as clamp force, four pull bars bear the summation determination clamp force P of tensile force f, the pulling force of setting four pull bars is respectively F
1, F
2, F
3, F
4, then clamp force P is: P=F
1+ F
2+ F
3+ F
4;
If half bridge measurement:
If full bridge measurement:
Sometimes in order to structural simplification, under the stressed the same hypothesis of each pull bar, only measure as clamp force using the measurement of a draw-bar pull, then adopt the clamp force of half-bridge and full-bridge connection to be respectively with the relation measuring output voltage:
If half bridge measurement:
If full bridge measurement:
D) relation of the pull bar distortion Δ l that clamp force P causes is set up, the tensile force f that above-mentioned relation and pull bar raw footage l, pull bar are subject to, the diameter d of pull bar self or cross-sectional area A (A=π d
2/ 4), the elastic modulus E of material therefor is relevant, is specifically expressed as:
Δl=εl=Fl/EA=4Fl/Eπd
2;
When measuring using the measurement of four draw-bar pulls as clamp force, and each pull bar is stressed identical, under the hypothesis that elongation is identical, that is:
then Δ l=ε l=Fl/EA=Pl/E π d
2;
E) at the end of the supercharging of press casting procedure, the actual clamp force P produced
realwith setting clamp force P
ifinconsistently just mean that above-mentioned Δ l does not reach set-point; The then difference of Δ l, also namely need regulate value be:
F) actual clamp force P
realwith setting clamp force P
ifrepresent with measured value, and set the summation of output voltage as u
total O, corresponding to actual clamp force P
realwith setting clamp force P
ifoutput total voltage be respectively u
real total Oand u
if total O, the difference of pull bar elongation represents have for different measurement situations with the voltage measuring clamp force:
If half bridge measurement
If full bridge measurement
G) actual clamp force difference and the difference that causes pull bar to be out of shape realizes regulating by the action of mode transfer executing agency; If the corner of hydraulic motor is θ, the step-down ratio between mode transfer executing agency gear is i, and the pitch of adjustment nut is t, then the relation between hydraulic motor corner θ and adjustment nut displacement s can be expressed as:
when regulated quantity s is pull bar modified difference Δ l
difference, hydraulic motor needs the angle regulated
Just have corresponding to different clamp force metering systems:
Suitably increase adjusting angle to be convenient to carry out regulable control, be also conducive to improving degree of regulation.Because the long l of pull bar limits by structure and rigidity, the u of test macro
e, s and v restrict clamp force test signal u simultaneously
osize.Therefore, increase the approach of adjusting angle mainly increase the speed reducing ratio of mould adjusting mechanism and adopt the adjustment nut of fine pitch.
The stability contorting of clamp force is realized by feedback control system.First control system compares the voltage difference (u that clamp force setting value and actual value difference produce
if total O-u
real total O), according to the above-mentioned locked mode provided with adjustment mould adjusting mechanism angular adjustment relation with controls basic demand, work out control program hydraulic control motor action; Detect with the coaxial mounted encoder of hydraulic motor and the angle that turns over of feedback hydraulic motor, the corresponding rotational angle of stable mode-locking power required adjustment deflection is provided.
A kind of die-casting machine die-locking power on-line control device that the present invention obtains and adjustment algorithm, very high precision can be obtained, this depends primarily on the precision of detection system, generally can make clamp force reach ± 3%, greatly improve and ensure the quality of die cast product, simultaneously compact conformation of the present invention, configure reasonable, safe and reliable, easy to use.
A kind of die-casting machine die-locking power on-line control device that the present invention obtains and adjustment algorithm, can detection and control in real time, carrying out regulating in matched moulds pressurization needs to adopt the hydraulic motor of high pulling torque to drive because clamp force is larger, adopts in actual use carry out zero load adjustment in next circulation because of uneconomical.
Described clamp force is often subject to operating temperature, motlten metal performance and the various factors such as capacity, diecast section hydraulic pressure, the large minor swing of clamp force also belongs to normal, in practical application, the margin of tolerance not affecting quality of item should be specified, for normally need not regulate in the margin of tolerance, tolerance range belongs to abnormal outward should consider whether regulate in time.
Described clamp force is abnormal refers to that the clamp force detected exceedes the limited margin of tolerance.Clamp force is overproof may be the impact of the accidentalia such as hydraulic system, feed.Often occur extremely just carrying out clamp force adjustment, regulate clamp force to be not effective measures to production of articles quality, also can to accelerate the wearing and tearing of die casting machine mould adjusting mechanism and mode transfer precision is reduced simultaneously so too continually.Consider the impact of accidentalia, should reason be analyzed to locked mode error, advise to have in continuous 2 overproof or five actions of clamp force three times overproof time take mode transfer action.
The accurate adjustment joint of the pulling force of each pull bar when described clamp force control method can be used for assembling.Utilize the force cell installed on each pull bar, measure the pulling force that each pull bar bears.When suffered by each pull bar, load is inconsistent, the pull bar attaching nut of manual adjustments pull bar front end, makes load suffered by each pull bar consistent, ensures the uniform force of die casting machine, improve equipment performance.
Detailed description of the invention
Below in conjunction with drawings and Examples, the present invention is further described.
Clamping mechanism shown in Fig. 1 is made up of front template 2, moving platen 3, rear pattern plate 5, and four pull bars (also known as guide pillar or grain post) 8 are run through wherein.Elbow-bar mechanism 4 promotes moving platen 3 matched moulds extrusion molten metal and produces clamp force P under the effect of die cylinder 9.At matched moulds at the end, the distance between front template 2 and moving platen 3 is the gross thickness of die casting duty bed die, and the spacing between moving platen 3 and rear pattern plate 5 is the axis projection of elbow-bar mechanism 4 duty when stretching out extreme position.In working order due to the effect of locked mode, locking mechanism in casting machine and pull bar 8 interact, and mould and elbow-bar mechanism 4 pressurized produce compression, and pull bar 8 deformed in tension extends, and produce tension.
Shown in Fig. 2 is mould adjusting mechanism transmission sketch.Its effect is the position changing rear pattern plate 5, and it is the installation requirement meeting different-thickness mould that macroscopic view regulates, and trace regulates to obtain different clamp force requirements.Mode transfer executing agency 1 is made up of the mode transfer pinion 6 on pull bar 8, adjustment nut 7, mode transfer gear wheel 10, driven wheel 11, speed reducing machinery 12, hydraulic motor 13 and encoder 14.Hydraulic motor 13 drives driven wheel 11 through reducing gear 12, drive mode transfer gear wheel 10 to rotate, mode transfer gear wheel 10 engages with the mode transfer pinion 6 on each pull bar 8 simultaneously, and mode transfer pinion 6 drives adjustment nut 7 to rotate, thus drive four adjustment nuts 7 to rotate simultaneously, rear pattern plate 5 is moved.Adjustment nut 7 rotates and advances, and rear pattern plate 5 is moved forward, and front template 3 and the hypotelorism of rear pattern plate 5, adapt to the installation of small size mould or improve clamp force, otherwise, adapt to large scale mould and install or reduce clamp force.The effect of encoder 14 is the corners detecting and be convenient to hydraulic control motor 13.
Shown in Fig. 1 is strain-type force sensor 15-1.The stress-strain state at each position of pull bar 8 is identical in theory, and the Stress distribution in fact near two end fulcrums is uneven, therefore requires that H distance template edge, its installation site is greater than pull bar 8 diameter d.Strain-type force sensor 15-1 position should not affect production of articles simultaneously, and few impact being subject to or not being subject to environment, is often arranged near rear pattern plate 5 place.
Strain-type force sensor 15-1 bis-end steel band 17 is connected on pull bar 8 tightly, makes it produce distortion with pull bar 8, ensures to be out of shape with pull bar 8 to be consistent as far as possible.
The 15-1 of strain-type force sensor shown in Fig. 3 is the one group of foil gauge be attached on flexible member 17 in essence, two foil gauges adopting a vertical and one horizontal to paste or employing right angle foil gauge.Elastic part material will keep the same with pull bar 8 material therefor material and performance as far as possible.The foil gauge longitudinally arranged experiences the identical stretching strain ε of pull bar 8, and the foil gauge of lateral arrangement experiences the compressive strain-v ε produced in responsive to axial force cross-direction shrinkage.
Figure 3 shows that the wiring diagram of strain-type force sensor 15-1.Use one group of strain-type force sensor 15-1 to adopt half bridge measurement, another two brachium pontis access the measuring resistance (or replacing with similar foil gauge) with foil gauge similar resistance.Half-bridge connection electric bridge is low in sensitivity, cannot offset the impact of the mechanics such as moment of flexure, but can eliminate temperature impact, realizes temperature-compensating; Use two groups of strain-type force sensor 15-1, as long as then two groups of strain-type force sensor 15-1 are connected, form full bridge measurement, the foil gauge longitudinally arranged is in relative edge, the foil gauge of lateral arrangement is on another relative edge, and full-bridge arrangement can the impact of the perturbed force such as compensate for temperature effects and moment of flexure.After strain-type force sensor 15-1 is connected into electric bridge, at four points of connection place connection signal line, an one diagonal angle access bridge power supply, another sends into controller 16-2 to angle point as output signal, as actual measurement clamp force signal, represents clamp force size.
The present embodiment additionally provides a kind of control algolithm of die-casting machine die-locking power on-line control device, and it is using the measurement of four pull bar 8 pulling force as the measurement of clamp force, and it specifically comprises the following steps:
Relation between the tensile force f that the pull bar 8 a) setting up locking mechanism in casting machine is subject to and the strain stress that pull bar 8 produces, the diameter d of above-mentioned relation and pull bar 8 self or cross-sectional area A (A=π d
2/ 4), the elastic modulus E of material therefor is relevant:
Its physical relationship formula is: ε=F/EA=4F/E π d
2or F=ε EA=E π d
2ε/4;
By Hooke's law, for the pull bar 8 by axial tension effect, its axial normal strain is ε, and transverse strain is-v ε, and wherein v is Poisson's ratio;
B) Strain Method is adopted to measure the actual pulling force of pull bar 8, pull bar 8 is fixed one group or two groups of strain-type force sensor 15-1, the above-mentioned strain-type force sensor 15-1 mentioned is made up of two foil gauges, a slice is along the longitudinal direction impression axial strain identical with pull bar 8 of pull bar 8 axis, and another sheet is experienced transverse strain and is combined into electric bridge and measures;
Adopt one group of strain-type force sensor 15-1 to connect into the strain of measuring bridge measurement pull bar 8, measuring circuit forms half-bridge, its strain stress and bridge output voltage u
0pass be:
In formula: u
efor supplying bridge voltage; S is foil gauge sensitivity; V is the Poisson's ratio of measured piece;
Two groups of strain-type force sensor 15-1 are adopted to connect into the measuring bridge form of full-bridge, its strain stress and bridge output voltage u
0pass be:
For concrete measuring object and test circuit u
e, s, (1+v) be definite value, if
be called electric bridge coefficient, then adopt one group of strain-type force sensor 15-1, half bridging method coefficient is k, adopt two groups of strain-type force sensor 15-1, full-bridge connection, coefficient is 2k;
According to the output voltage of measuring circuit and measurement, suffered by the pull bar 8 that can obtain measuring gained, pulling force is:
One group of strain-type force sensor 15-1 (half bridge measurement):
Two groups of strain-type force sensor 15-1 (full bridge measurement):
C) the clamp force P described in be on die casting machine four pull bars 8 bear the summation of tensile force f.Respectively device for measuring force is set on each pull bar 8, measures the tensile force f of each bar respectively
1, F
2, F
3, F
4, then clamp force P is: P=F
1+ F
2+ F
3+ F
4
If half bridge measurement:
If full bridge measurement:
D) relation that pull bar 8 that clamp force P causes is out of shape Δ l is set up, the tensile force f that above-mentioned relation and pull bar 8 raw footage l, pull bar 8 are subject to, the diameter d of pull bar 8 self or cross-sectional area A (A=π d
2/ 4), the elastic modulus E of material therefor is relevant, is specifically expressed as:
Δl=εl=Fl/EA=4Fl/Eπd
2;
Stressed identical at each pull bar 8, under the hypothesis that elongation is identical, that is:
then Δ l=ε l=Fl/EA=Pl/E π d
2;
E) at the end of the supercharging of press casting procedure, the actual clamp force P produced
realwith setting clamp force P
ifinconsistently just mean that above-mentioned Δ l does not reach set-point; The then difference of Δ l, also namely need regulate value be:
F) actual clamp force P
realwith setting clamp force P
ifrepresent with measured value, and set the summation of output voltage as u
total O=u
01+ u
02+ u
03+ u
04, corresponding to actual clamp force P
realwith setting clamp force P
ifoutput total voltage be respectively u
real total Oand u
if total O, the difference of pull bar 8 elongation represents have for different measurement situations with the voltage measuring clamp force:
If half bridge measurement
If full bridge measurement
G) actual clamp force difference and the difference that causes pull bar 8 to be out of shape realizes regulating by the action of mode transfer executing agency 1; If the corner of hydraulic motor 13 is θ, the step-down ratio between mode transfer executing agency 1 gear is i, and the pitch of adjustment nut 7 is t, then the relation between hydraulic motor 13 rotational angle theta and adjustment nut 7 displacement s can be expressed as:
when regulated quantity s is pull bar 8 modified difference Δ l
difference, hydraulic motor 13 needs the angle regulated
Just have corresponding to different clamp force metering systems:
Embodiment 2:
A kind of die-casting machine die-locking power on-line control device that the present embodiment provides and adjustment algorithm, its general structure is consistent with embodiment 1, difference is in the die-casting machine die-locking power on-line control algorithm that the present embodiment provides, under the stressed the same hypothesis of each pull bar 8, only measure using the measurement of pull bar 8 pulling force as clamp force, it specifically comprises the following steps:
Relation between the tensile force f that the pull bar 8 a) setting up locking mechanism in casting machine is subject to and the strain stress that pull bar 8 produces, the diameter d of above-mentioned relation and pull bar 8 self or cross-sectional area A (A=π d
2/ 4), the elastic modulus E of material therefor is relevant:
Its physical relationship formula is: ε=F/EA=4F/E π d
2or F=ε EA=E π d
2ε/4;
By Hooke's law, for the pull bar 8 by axial tension effect, its axial normal strain is ε, and transverse strain is-v ε, and wherein v is Poisson's ratio;
B) Strain Method is adopted to measure the actual pulling force of every root pull bar 8, pull bar 8 is fixed one group or two groups of strain-type force sensor 15-1, the above-mentioned strain-type force sensor 15-1 mentioned is made up of two foil gauges, a slice is along the longitudinal direction impression axial strain identical with pull bar 8 of pull bar 8 axis, and another sheet is experienced transverse strain and is combined into electric bridge and measures;
Adopt one group of strain-type force sensor 15-1 to connect into the strain of measuring bridge measurement pull bar 8, measuring circuit forms half-bridge, its strain stress and bridge output voltage u
0pass be:
In formula: u
efor supplying bridge voltage; S is foil gauge sensitivity; V is the Poisson's ratio of measured piece;
Two groups of strain-type force sensor 15-1 are adopted to connect into the measuring bridge form of full-bridge, its strain stress and bridge output voltage u
0pass be:
For concrete measuring object and test circuit u
e, s, (1+v) be definite value, if
be called electric bridge coefficient, then adopt one group of strain force cell 15-1, half bridging method coefficient to be k, adopt two groups to strain force cell 15-1, full-bridge connection, coefficient is 2k;
According to the output voltage of measuring circuit and measurement, suffered by the pull bar 8 that can obtain measuring gained, pulling force is:
One group of strain-type force sensor 15-1 (half bridge measurement):
Two groups of strain-type force sensor 15-1 (full bridge measurement):
C) under the stressed the same hypothesis of each pull bar 8, only measure using the measurement of pull bar 8 pulling force as clamp force, described clamp force P is the tensile force f that on die casting machine, a pull bar 8 bears.A pull bar 8 arranges device for measuring force, measures the tensile force f of this pull bar 8
1, then clamp force P is: P=F
1;
If half bridge measurement:
If full bridge measurement:
D) relation that pull bar 8 that clamp force P causes is out of shape Δ l is set up, the tensile force f that above-mentioned relation and pull bar 8 raw footage l, pull bar 8 are subject to, the diameter d of pull bar 8 self or cross-sectional area A (A=π d
2/ 4), the elastic modulus E of material therefor is relevant, is specifically expressed as:
Δl=εl=Fl/EA=4Fl/Eπd
2;
When measuring using the measurement of four pull bar 8 pulling force as clamp force, and each pull bar 8 is stressed identical, under the hypothesis that elongation is identical, that is:
then Δ l=ε l=Fl/EA=Pl/E π d
2;
E) at the end of the supercharging of press casting procedure, the actual clamp force P produced
realwith setting clamp force P
ifinconsistently just mean that above-mentioned Δ l does not reach set-point; The then difference of Δ l, also namely need regulate value be:
F) actual clamp force P
realwith setting clamp force P
ifrepresent with measured value, and set output voltage as u
total O, corresponding to actual clamp force P
realwith setting clamp force P
ifoutput total voltage be respectively u
real total Oand u
if total O, the difference of pull bar 8 elongation represents have for different measurement situations with the voltage measuring clamp force:
If half bridge measurement:
If full bridge measurement:
G) actual clamp force difference and the difference that causes pull bar to be out of shape realizes regulating by the action of mode transfer executing agency 1; If the corner of hydraulic motor 13 is θ, the step-down ratio between mode transfer executing agency 1 gear is i, and the pitch of adjustment nut 7 is t, then the relation between hydraulic motor 13 rotational angle theta and adjustment nut 7 displacement s can be expressed as:
when regulated quantity s is pull bar 8 modified difference Δ l
difference, hydraulic motor 13 needs the angle regulated
Just have corresponding to different clamp force metering systems:
。